Polymaleic anhydride prepared by γ‐rays irradiation of maleic anhydride was used as a reactive polymer and reacted with certain long‐chain aliphatic amines and/or alcohols as well as with the mesogenic biphenylamine. The homopolymers and copolymers that were prepared, i.e., derivatives of N‐alkyl polymaleamic acid, monoesters of polymaleic acid, or mixed amide‐ester derivatives, were primarily investigated as far as their property to show thermotropic liquid crystalline character is concerned. By this investigation the structural features for the exhibition of mesomorphism by these polymers were determined. Copyright © 1990 John Wiley & Sons, Inc.